STEP 1: Create a Mesh (Plane) as in FIG.1
STEP 2: Keep the Object active and select the WRAP Feature. Automatically the Object will connect to the DOME Ground. (FIG.2)
STEP 3: Move the object and the terrain wrapped to it will follow in any direction you move. It is especially intended to move on the Z-Axis allowing to create any kind of ground depression. (FIG.3) The object is visible and clicking on the Hide button it will
STEP 4: In (FIG.3) the object is visible and by clicking on the Hide button it will disappear as shown in FIG.
NOTE: The UNWRAP Feature releases the object from being attached to the DOME ground
FIG.5: In this figure are indicated the Plane Mesh to which is wrapped the terrain and above it there is a Second Plane Mesh that we created in HDRi. Using the EXTREME PBR Add-on, to the Second plane mesh, we applied a WATER material.
FIG.6: Being, the Second Plane Mesh, underneath the ground level, it generates a water filling effect in the ground depression created by the Plane Mesh originally wrapped. Selecting the Second Plane Mesh in the Outliner, by clicking HIDE within the HDRI Background projection menu, the water effect can be hidden or seen in the scene.
FIG.7 & FIG.8: If for example you add to your scene an object such a landscape created with the A.N.T. Landscape Add-on (FIG.7), by clicking the Ground button, having the object selected, the background is automatically applied as seen in FIG.8. Using the Remove button will remove it from the selected object.